Studies of coagulation of blood and its components are of great practical interest because they do not only allow certain diseases to be diagnosed but also make it possible to assess the activity of preparations affecting blood coagulation parameters. Various devices for determining coagulation rate in whole blood and in plasma are known from the background art. However, up to this day, these studies have been designed in a homogenous system with permanent mixing. As the whole volume of plasma is permanently mixed from the beginning of the test and until the end thereof, all coagulation factors formed during the process of formation of a plasma clot are homogenously distributed in the test medium, and the clot formation is ongoing simultaneously in the whole volume of the test sample. From the physiological point of view, this process is fundamentally different from conditions of clot formation in vivo.
From the background art, we know an apparatus for monitoring the spatial fibrin clot formation disclosed in international application PCT/CH2007/000543 (international publication WO 2009/055940, cl. G01N 33/49, published on May 7, 2009). The apparatus contains a cuvette assembly consisting of a cuvette and an insert with coagulation activator immobilized on the bottom end of the insert. The cuvette assembly is placed in a holder comprising a thermostat for thermal stabilization of the cuvette and devices for fixing the cuvette inside the thermostat. The thermostat is filled with an at least partly transparent fluid. The said apparatus allows registering of the process of formation of a fibrin clot being the final product of work of the coagulation system without providing a possibility to register the process of formation and spatial distribution of other coagulation factors regulating the process of spatial growth of a fibrin clot. The closest analog to the disclosed solution is the device for investigation of coagulation characteristics of blood and its components (patent RU 2395812, cl. G01N33/49, published on Jul. 27, 2010) comprising a thermostatically controlled chamber filled with fluid and accommodating a cuvette with a test sample and an insert with the immobilized coagulation activator, a means of illumination to lighten the contents of the cuvette and the clot formed close to the lower end of the insert, and a digital camera; the device is connected with a computer to process the obtained data.
Disadvantages of the said device include formation of gas bubbles in the test samples and in the fluid, within the registration area, during heating of the test samples in a thermostatically controlled chamber: these bubbles distort the light scattering signal from the fibrin clot. Moreover, the device contains a means of illumination with only one wavelength, for example, red light, which prevents studying spatiotemporal distribution of proteolytic enzymes, for example, with fluorescent methods, simultaneously with the study of fibrin clot formation.